The present invention relates to a pulse jitter reduction circuit which is employed as a last stage synchronizer for synchronizing a pulser circuit for a time-of-flight (TOF) mass spectrometer with the data acquisition circuits to improve the signal resolution of the spectrometer.
A TOF mass spectrometer relies upon precise timing between the high voltage acceleration pulse applied to the flight tube to accelerate ions along the flight tube and the subsequent detection of the time of arrival of the ions by the data acquisition system. The high voltage pulse employed for accelerating the ions, therefore, must be synchronized with the data acquisition timing, such that ions corresponding to particular elements can be accurately identified. The more precise the timing relationship of the respective signals, the more precise and higher the resolution of the mass spectrometer. With conventional pulse-trigger systems employed to provide the high voltage pulses to the flight tube, inherent uncertainty exists in the pulse initiation. This inherent fluctuation in the pulse initiation time is referred to as “jitter” and is a limiting factor of the resolution of a TOF mass spectrometer. Jitter as high as 100 pico seconds (ps) or higher is common and adversely affects the resolution of a mass spectrometer, particularly where samples having closely grouped elemental ions are involved.
Thus, there exists a need for an improved triggering circuit which eliminates or greatly reduces jitter existing in conventional triggering circuits.